Distributed computer environments attempt to harness the power of several computers in order to perform desired processing tasks. Oftentimes, this usage model enables several computers to collaboratively perform computationally intensive tasks within substantially reduced amounts of time. Generally, the divide and conquer approach provided by parallel computing enables utilization of available personal computers, rather than purchasing of a high performance, server-based computer system for performing the computationally intensive tasks.
Until recently, the only collaborative usage model for multiple personal computers (PCs) was based on distributing purely computational tasks. As such, distributed computing has generally not been applied to synchronized capture and/or processing of signals, especially audio/video signals (and data streams). In general, signal processing of audio and video signals (multimedia data) is very sensitive to time jitters, delays and drifts. As a result, signal processing for such multimedia data requires precise synchronization for high quality input/output processing, as well as robustness and reliability issues.
Unfortunately, precise capture and synchronization of inputs as well as precise rendering and synchronization of outputs is not guaranteed on current platforms. As a result, new usage paradigms for PCs, personal digital assistants (PDAs), Tablets and the like, as devices for collaborative signal processing of multimedia signals are generally not available. For example, signal processing on a common PC platform can lead to several problems when several I/O devices are used to capture audio and visual information utilizing, for example, video cameras and microphones.
As such, various problems arise due to the fact that different I/O devices will be triggered by separate oscillations. Unfortunately, the separate oscillations cause resulting audio samples and video frames to be unaligned along an absolute timeline, thereby inducing some relative offsets. Moreover, due to differences in oscillator frequencies, audio and visual data will drift away across multiple channels and streams over time. Likewise, multimedia signal processing within multiple PC platforms can lead to several problems.
Within multiple PC platforms, audio and visual I/O devices will not be synchronized in time scale, which will cause data samples to drift and/or be shifted relative to each other. The extent of the shift, jitter and/or drift on the existing platforms depends on hardware and software parameters and can be very significant, sometimes causing total degradation of the processed signals from the non-synchronized input streams. Such drifts, delays and/or jitters can cause significant performance degradation for, for instance, array signal processing algorithms.
For example, in an acoustic beam former with 10 centimeter (cm) spacing between microphones, an error of only 0.01 percent in time can cause error of 20 degrees in the beam direction. Due to this fact, current implementations of audio array process algorithms rely on dedicated circuitry for the synchronization between multiple I/O channels. Unfortunately, implementing such an approach with existing PC platforms would require a major overhaul of the current hardware utilized by the PC platforms. Therefore, there remains a need to overcome one or more of the limitations in the above-described, existing art.